1. Field of the Invention
The present invention relates to a dielectric thin film having excellent optical characteristics such as a refractive index and a transmittance and, more particularly, to a zinc sulfide thin film having improved optical characteristics and a method of manufacturing the same.
2. Description of the Related Art
Zinc sulfide (ZnS) is known as a material having a high transmittance and a high refractive index, and a thin film consisting of ZnS is used as, e.g., an anti-reflection film, a wide-band mirror, a waveguide, a micro lens, and a Kerr rotation angle enhancing film.
A conventional ZnS thin film consists of only zinc (Zn) and sulfur (S) at a composition ratio of 1:1 and is formed by a vacuum evaporation method or a sputtering method. A refractive index of such a conventional ZnS thin film is reported to be as high as 2.30 to 2.35.
In the applications described above, however, as the refractive index is increased, the film thickness of the thin film or the number of thin films can be decreased, and a manufacturing cost can be decreased accordingly. Therefore, a demand has arisen for development of a dielectric thin film having a higher refractive index and a higher transmittance.